Google Voice is a great service for anyone with more than one phone number. But it's especially useful to prepaid users, who tend to switch operators a lot and worry about losing their numbers while porting or if a new MVNO goes bust. Google Voice gives you:

A single "phone number for life" which you can set to ring any or all of up to 6 mobile, landline or VOIP phone numbers.

SMS forwarding. Text messages sent to your Google Voice number are forwarded to the mobile numbers you specify and/or to an email address.

Send free (except for the cost of data) texts to U.S. and Canadian numbers from the Google Voice Android and iOS apps and web and mobile web sites.

Get email notifications of voice mails with an attached audio file and a speech to text transcription of the voice mail.

Screen calls and block specific callers

Google voice also provides:

Web and Mobile Web administration pages where you can change which phones your Google Voice number rings, temporarily block calls or divert them to a new number, view call records, view transcribed voice mails or listen to recordings of them and manage and place calls from your Google Voice phone book

Android and iOS apps that let you view and listen to voicemails, send texts and make calls using your Google voice number

Low cost (competitive with Skype and other VOIP services) international long distance calling

Make free long distance calls from any phone by calling your Google Voice number, pressing * and choosing "make call" from the menu.

The one thing that traditionally hasn't worked very well in Google Voice is MMS (picture messaging). MMS is a cellular protocol that was not designed to work with third party services like Google Voice. If you send an MMS to a Google Voice number the message typically just disappears. To the sender it looks like the message was sent but the intended recipient never sees any sign of it.

For MMS to work with Google Voice, mobile operators have to modify their systems to forward MMS to Google's gateway. The operators have been reluctant to do that. Two years ago Google finally managed to get Sprint to support MMS to Google Voice numbers and this week T-Mobile got on board too.

Now sending an MMS from Sprint and T-Mobile phone to a Google Voice number works, sort of. When Voice gets an MMS from a supported network it doesn't forward the message as a MMS to the user's forwarding phone. Instead the MMS goes Google Voice user's email with the picture, video or other attachment included. You also get a text in the Google Voice app notifying you that an MMS was received. It's a little kludgy but it works.

A neat thing about Google Voice's integration with Sprint and T-Mobile is that it works with those carrier's prepaid brands and MVNOs too. I tested sending a picture message to my Google Voice account from my Boost Mobile, T-Mobile prepaid and PTel (a T-Mobile MVNO) phones and all three pictures were delivered to my Gmail account.

I also discovered a cool undocumented feature. Google Voice's integration with T-Mobile lets you send an MMS from your email account. For this to work you need to be replying to a Google Voice MMS email. When you reply (with a different picture if desired), it goes to the T-Mobile phone as a real MMS. Replying to MMS emails received from Sprint based phones doesn't seem to work, I got a Google Voice error when I tried to reply to an MMS I'd received from my Boost phone.

There are more changes coming to Google Voice. Google Voice is getting integrated into Google Hangouts. iPhone users can already make VOIP calls with their Google Voice number using the Hangouts iOS app. Google says that by early next year both Android and iOS users will be able to send and receive SMS and MMS from their Google Voice numbers using Hangouts. Google is also saying that effective May 15, 2014, it will begin blocking third-party apps like Talkatone, and GroveIP that add VOIP calling to Google Voice. That suggests to me that Google is planning to implement its own VOIP calling solution, probably in Hangouts, before May 15.

I would love it if I could trust Voice, but twice I tried to use it as my main number (as a test with family members) and I discovered that some calls never went through and messages disappeared. My testers reported that sometimes they would receive a vague message about my number not being in service. Maybe it has to do with where we are located or some other factor, but I just can't trust the service enough to make it my main number. I still use it as a back up system for calling, like when I need to call my cell carrier when my cell phone isn't working. It is also handy to be able to send texts from my PC.

Interesting to see Google breathing new life into Voice after letting it sit moribund for so long. I was thinking about porting my number out, but now will wait until next year to see what develops. Adding more MVNOs to the MMS service would be great.

I couldn't get Google Voice to work at all, could not find a way to dial numbers on it. I bought a 99 cent app that let me do this. Made Google Voice seem like some sort of driver system as opposed to an actual program.

About the first paragraph: is losing numbers due to bad porting or dying MVNO's really something to worry about?

For Android and iOS users, if the Google Voice name disappears after it's features become part of Hangouts it's a good thing. Hangouts are one of Google's current premier products. If messaging and VOIP calling become part of Hangouts they will be maintained and expanded. Google Voice as a stand alone product was neglected and at risk of being killed.

Killing GV would be bad for people who use it on other platforms, mainly Windows Phone and home phone replacement products like Obihai. I blame Microsoft which has made itself Google's target with its lawsuits against Android vendors. Obihai etc. are getting caught in the crossfire between Google and Microsoft.

All comments must be approved before they will appear. The following types of comments will not be approved: off topic comments, insults or personal attacks directed at other commenters, bigotry, hate, sexism and profanity.